Determining the role of the mechano-activated potassium channel TRAAK at nodes of Ranvier

确定机械激活钾通道 TRAAK 在 Ranvier 节点的作用

• 批准号: 10680260
• 负责人: Anna Virginia Elleman
• 金额: $ 6.91万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10680260
• 关键词: Action Potentials; Acute; Axon; Binding Sites; Biochemical; Biophysics; Cells; Communication; Cysteine; Data; Development; Disease; Electrophysiology (science); Exhibits; Functional disorder; Future; Glaucoma; Goals; Guillain Barré Syndrome; Isomerism; Libraries; Ligands; Light; Location; Maleimides; Measures; Mechanical Stimulation; Mechanics; Mediating; Membrane; Molecular; Multiple Sclerosis; Nature; Nerve; Nervous System Physiology; Neurons; Nodal; Optic Nerve; Organic Chemistry; Pathology; Physiologic pulse; Positioning Attribute; Potassium; Potassium Channel; Process; Ranvier' s Nodes; Refractory; Research; Role; Series; Signal Transduction; Site; Specificity; Speed; Spinal Injuries; Stretching; Stroke; Swelling; TRAAK channel; Tetraethylammonium; Viola; Work; azobenzene; design; experimental study; extracellular; flexibility; improved; inhibitor; mechanical force; mutant; nervous system disorder; neurophysiology; novel; patch clamp; response; screening; spatiotemporal; tool; voltage

Abstract Action potential propagation through nodes of Ranvier is central to nervous system function. Understanding this process is essential for developing improved treatments for nodal pathologies of electrical signaling including multiple sclerosis, Guillain-Barré syndrome, stroke, spinal injury, and glaucoma. Saltatory conduction—the jumping of the action potential from one node to the next—has been described since its discovery as a purely electrical phenomenon. This proposal aims to investigate whether it is also fundamentally mechanical in nature. The mechano-activated two-pore domain potassium channel TRAAK is exclusively expressed at nodes of Ranvier. TRAAK is insensitive to voltage, but acutely tuned to membrane tension, with cell swelling increasing TRAAK-mediated potassium currents up to one hundred-fold. Still, whether mechanical activation of TRAAK is relevant to spike propagation is unknown. Using a combination of organic chemistry, molecular biophysics, and neurophysiology, this proposal will examine how mechanically activated TRAAK currents contribute to action potential propagation, speed, and reliability. To selectively control TRAAK channels, photoswitchable tethered ligands (PTLs) will be designed, synthesized, and optimized for maximal spatiotemporally precise block of TRAAK current. Screening of PTL tethering sites in leak and mechano-activated open TRAAK channels will enable the identification of state-specific PTL·Cys-TRAAK pairs and the precise modulation of basal and/or mechano-activated TRAAK currents. Using these tools, TRAAK's contributions to action potential propagation will be characterized in myelinated optic nerve under typical conditions and in response to mechanical perturbation. These experiments will both elucidate the role of TRAAK in spike propagation and, potentially, demonstrate that mechanical force is central to node repolarization, with broad implications for the treatment of nodal pathologies and the field of neuronal communication as a whole.

摘要 动作电位通过兰维尔结节的传播是神经系统功能的中枢。理解这一点 过程是开发改进的电信号结节病理治疗方法的关键，包括 多发性硬化症、格林-巴利综合征、中风、脊柱损伤和青光眼。跃迁传导-- 动作电位从一个节点跳到下一个节点--自发现以来一直被描述为一种纯粹的 电学现象。这项提议旨在调查它是否从根本上也是机械性质的。 机械激活的双孔结构域钾通道TRAAK仅在 兰维尔。TRAAK对电压不敏感，但对膜张力有很强的调节作用，细胞膨胀率增加 TRAAK介导的钾电流高达100倍。尽管如此，机械激活TRAAK是否 与穗传播相关的信息尚不清楚。使用有机化学、分子生物物理学和 神经生理学，这项建议将研究机械激活的TRAAK电流如何对动作做出贡献 潜在的传播、速度和可靠性。为了选择性地控制TRAAK通道，光可切换系绳 配体(PTLS)将被设计、合成和优化，以最大限度地在时空上精确地阻断 TRAAK电流。将在泄漏和机械激活的开放TRAAK通道中筛选PTL系留部位 能够识别特定状态的PTL·Cys-TRAAK对并精确调节基础和/或 机械激活的TRAAK电流。使用这些工具，TRAAK对动作电位传播的贡献 在典型情况下会在有髓视神经中表现出来，并对机械性 微扰。这些实验将阐明TRAAK在穗繁殖中的作用，并有可能， 证明机械力是结节复极的中心，对治疗结节复极有广泛的意义。 作为一个整体的结节病理学和神经元通讯领域。